The present invention relates generally to storage systems involving thin provisioning and, more particularly, to methods and apparatus for managing object-based tiers.
In recent years, thin provisioning has become popular. Thin provisioning is a method for allocating fixed size area when a storage subsystem receives a write command to unallocated area. Prior art allows the storage subsystem to migrate frequently accessed allocated fixed size area to fast and expensive media and to migrate rarely accessed allocated fixed size area to slow and cheap media.
An application program frequently accesses some application objects and rarely accesses the other application objects. There are frequently accessed objects and infrequently accessed objects in one allocated fixed size area. As a result, the access frequency of the allocated fixed area becomes between frequent and infrequent. Therefore the frequently accessed objects are not moved to fast media and the infrequently accessed objects are not moved to cheap media.